Machines, such as passenger vehicles, trains, off-highway trucks, and mining vehicles, often employ hydraulic systems that provide functionality and control to various aspects of the machines. For example, some machines employ hydraulic braking systems to control driving speeds. These hydraulic braking system may include a fluid pressurizing pump or other types of parasitic loads that derive power from the machine's power source, namely, an engine. The braking system may generate an associate efficiency loss for the engine due to the pump and/or other parasitic loads.
One problem associated with this type of hydraulic arrangement involves starting of the machine when temperatures are low and/or altitudes are high, especially when the engine is also used to provide power to the other parasitic loads. There are known systems that include control systems associated with the operation of parasitic loads driven by an engine as the power source. For example, U.S. Pat. No. 6,920,387 to Landes et al. (hereinafter “'387”) provides a control system for determining the net power output of an engine associated with a work machine or other vehicle wherein parasitic loads encountered during engine operation are taken into account. Nevertheless, '387 and other known systems do not disclose control of hydraulic systems based on engine speed for improved machine performance in low temperatures and/or high altitudes.
The present disclosure is directed to overcome one or more of the problems as set forth above.